SOLUTION: This is my son'd hoework assignment, in the back of the book on page 803 in the extra practice section he has to solve proble # 18using linear combinations to solve linear equation

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Question 125832This question is from textbook Algebra I
: This is my son'd hoework assignment, in the back of the book on page 803 in the extra practice section he has to solve proble # 18using linear combinations to solve linear equations. The problem is:
3x+7y=-1
7y=-6x
If I rearrange the equation to solve it looks like this:
3x+7y=-1
-6x-7y=?
Now what do we do? This question is from textbook Algebra I

Found 3 solutions by checkley71, Earlsdon, josmiceli:
Answer by checkley71(8403)   (Show Source):
You can put this solution on YOUR website!
3x+7y=-1 now multiply the other equation by -1 [-7y=6x] now subtract -6x from both sides [-6x-7y=6x-6x. now you have 6x-6x=0 on the right side. now add these two equations.
3x+7y=-1
-6x-7y=0
----------------------------------
-3x=-1
x=-1/-6
x=1/6 answer.
7y=-6*1/6
7y=-1
y=-1/7 answer.

Answer by Earlsdon(6294)   (Show Source):
You can put this solution on YOUR website!
Solve using linear combinations:
1)
2)
You had the right idea in rearranging the second equation but the ? should be a 0, as in:
2) Now you add the two equations:

---------------
Now divide both sides by -3.
Now substitute this value of x into either one of the two original equations to solve for y. Let's use the second equation:
Substitute
Simplify.
Now divide both sides by 7.

Answer by josmiceli(19441)   (Show Source):
You can put this solution on YOUR website!
You're almost there

In the 2nd equation, you subtracted from both sides, and
that left on one side as you can see
Now just add the 2 equations

substitute this answer in either equation to find

check:

OK
and you can check other one